An asphalt, a process of making it and an enamel made therewith



naw-mm ocr. 16. 1956 suBsfrEurE FOR Missme XR M. H. EDsoN 2,767,102 AN ASPHALT. A PROCESS F MAKING IT AND n ENAMEL MADE THEREWITH Filed Nov. 28, 1952 murrcu {iff-:65cm 5ms/encor Cltftlorng SEARCH. ROOM AN ASPHALT, A PROCESS F MAKING IT AND AN ENAMEL MADE THEREWITH 2,767,102 Patented Oct. 16, 1956 ticularly deficient in requiring too high a temperature of application and they do not have sucient hardness.

Murray H. Edson, Rahway, N. I., assgnor to Esso Research and Engineering Company, a corporation of Delaware Application November z8, 1952, serial No. 322,919

4 claims. (ci. 10s- 281) The objects of this invention are a novel asphaltic composition, a process of making it and an improved enamel composition particularly adapted for use in the protective coating of pipelines. In this application of the invention,

The present invention is ltherefore concerned with ar new asphalt manufacturing process of a character to provide a novel asphalt having the unusual combination of physical properties referred to. The purpose is primarily to provide an asphalt uniquely qualified for use in pipe i line enamels. In accordance with these objectives, it has a thermal tar is obtained by vac-distilling the lighter constituents from the thermally cracked products. This thermal tar is then oxidized, as by blowing air through the tar, so as to provide the final asphalt product. This asphalt possesses an unique combination of physical properties. In general, the asphalt will possess a penetration (ASTM D5) of zero at 77 F./ 100 g./5" and less than 6 at 115 F./ 100 g./5", and a softening point of about 160 to 210 F. Enamels made from this asphalt are characterized by shatter resistance, slip resistance, hardness, and low application temperature.

At the present time a variety of processes are known for obtaining asphalts from crude petroleum oils.l Forv example, residual petroleum oils may be oxidized by airblowing to provide asphalts. Again, residual oils may be subjected to vacuum distillation so as to obtain asphalts. A variety of treating re-agents may also be employed to convert a residual oil to an asphalt. Each of the processes which may be employed for asphalt manufacture result in asphalts having a particular interrelation of physical properties. Thus, for example, asphalts obtained by the air-blowing of residual oils are characterized by high softening points, low temperature susceptibility, and high values of penetration. Asphalts obtained from the other processes indicated, possess somewhat different properties in these and other respects.

In order to obtain an asphalt having desirable properties for a particular application, it becomes valuable to develop unusual combinations of asphaltic properties. For example, in using an asphalt for a protective coating as in the enameling of a pipeline, it is important to ob-v tain an asphalt having a high shatter resistance so as to resist fracture due to back-filling or abrasion of the pipeline. Such an asphalt should also have sutlicient hardness to resist penetration by rocks, should have a low application temperature to facilitate field usage, a ash point above the application temperature, good sloughing" characteristcs to prevent slipping on the pipeline while cooling, and should not be susceptible to low temperature cracking. In general, presently known asphalts do not have the requisite combination of properties and are par- .s i P l been found that a new type of asphalt may be obtained by a particular processing sequence. Essentially, the required processing steps concern the catalytic cracking of a heavy boiling fraction of a crude petroleum oil. The

heaviest boiling fraction of the catalytically cracked gas oil is then subjected to a thermal cracking operation. Again, the heaviest boiling fraction obtained from the thermal cracking operation is employed and this fraction is subjected to distillation and air-blowing to provide the final asphalt. It is presently believed that the unusual asphalt properties characteristic of the iinal product are attributable to the chemical composition of the asphalt as a consequence of the treating steps. Thus, it is known that unlike asphalts obtained from other processes, the asphalt of this invention is characterized by a predominance of aromatic hydrocarbons boiling above about 700 F. The asphalts of this invention contain more than 95% of aromatic hydrocarbons. Thus, due to this unique chemical composition of the asphalts, unusual asphaltic properties are appreciated.

In the preferred form of this invention, an asphalt of the character described is admixed with an inorganic ller such as slate our and mica to provide an enamel. Both the slate flour and mica are employed in nely powdered form. The slate Hour preferably constitutes a powder of which 95% will pass through a 325 mesh screen, while 90% of the mica will pass through a 40 mesh screen and not more than through a 100 mesh screen. While varying proportions of mica and slate may l be used, it is particularly preferred to use about 20 to 40% of the slate flour and about 5 to 20% of mica admixed with the asphalt. As will be shown, an enamel constituting the particular asphalt of this invention in combination with the slate and mica flour possesses particularly desirable properties for pipeline enameling applications. It is to be understood however, that other fillers such as sand, clay, rock, etc., may be used in powdered form in place of the slate and mica ilour.

In order to fully disclose the nature of this invention, reference will be made to the accompanying drawing which diagrammatically illustrates the overall process for obtaining the compositions of this invention. In this drawing, a crude distillation zone 1 is depicted. A crude petroleum oil may be introduced to zone 1 through line 2. The distillation operation is conducted to permit removal of volatile fractions overhead through line 3 and of heavier boiling products such as gasoline, kerosene and heating oils through side stream withdrawals 4, 5, 6, and so on. The heavier boiling fractions having initial boiling ranges of from 800 to ll00 F. and higher are withdrawn as a side stream product through line 7. Residual oil fractions are withdrawn through line 8. It is particularly contemplated that in the practice of this Y invention, distillation zone 1 be of such a nature as to conducted to a catalytic cracking zone identified by the rectangle 9. The cracking operation to be conducted in vzone 9 is of any desired type vemploying a catalyst such as modified natural or synthetic clay or gel type catalysts.

Examples of these are montmorillonite clays, silica-- alumina, silica-magnesia composites, and other conventional cracking catalysts. The operation may be of a continuous or batch nature employing fixed beds, moving beds, tluidized, or suspensoid systems. The heat required for cracking may be supplied as preheat or processed materials and/or as the sensible heat of exothermically regenerated catalyst or in any other conventional manner. The cracking is carried out at temperatures of about 800 to 1000" F., and pressures of about atmospheric to 25 p. s. i. g. or higher. The total cracked products are removed from cracking zone 9 and are conducted `to a product fractionator 10. Fractionator 10 is operated to remove lighter fractions of the cracked products through overhead 11, side streams 12, 13, and so on. A bottoms 2,767,102 I Y fproducts of the thermal cracking operation can be subjected to distillation at atmospheric or higher pressure to remove light fractions prior to the vacuum reduction step.

The bottoms product withdrawn from flashing zone 3l is then conducted to an oxidation zone 34 wherein the material is oxidized to a desirable softening point. For this purpose air may be brought into zone 34 through line 35 so as to provide about 30 to 60 cu. ft. of air per minute per ton of asphalt.

' conducted at atmospheric pressures and at temperatures of about 400 F. to 600 F. To secure the objectives of l this invention, it is essential that the air-blowing be conducted to secure asphaltic material having a softening point of about 160 to 210 F., preferably 190 to 200 F. Either before or after the air-blowing step, a suitable ller is added to the asphalt to secure the linal i A. enamel composition. Preferably the filler is added to the product is obtained from fractionator 10 which may be j i removed through line 14. In the event the cracking operation conducted in zone 9 was of a fluidized nature,y the material withdrawn through line 14 will contain av small percentage of catalyst particles carried over from v zone 9. In this case, it is necessary to pass the product stream of line 14 to a settler 15 or otherwise to process the stream to permit separation of the liquid hydro-y carbon product from the catalyst. Thus, a clarified hydrocarbon stream is removed from zone 15 through line 16. For the purposes of this invention, the bottoms product of fractionator 10, corresponding to the streamv asphalt before air-blowing so that the air will mix and incorporate the filler in the asphalt. Thus, the filler may f be introduced directly into the oxidation zone through hopper 36 prior to or during air introduction. The final enamel product may then be withdrawn from zone 34 through line 37 after the oxidation has been completed.

In order to demonstrate the unique properties of the composition of this invention, the following data is given showing the properties of a representative enamel prepared in accordance with this invention. The enamel referred to composed 60% of an asphalt derived as illusfractory in nature and constitutes a very poor cracking feed, causing substantial deposition of carbon and coke on the catalyst employed during cracking. As will be appreciated therefore, it is one of the features of this invention to employ cycle oil so as to prevent recycling to a cracking operation and so as to provide valuable products.

As the conduct of the process as described heretofore is well known to the art, no further description of this phase of the process is considered necessary. The cycle oil of line 16 derived as indicated is then conducted to a thermal cracking zone 20. Zone 20 is employed to thermally crack the cycle oil in the conventional manner. Thus, for example, the thermal cracking zone may constitute a tired coil subjecting the cycle oil passed through to a temperature in the range between 850 and 1200" F., and to a pressure of about 300 to 1000 lbs. per square inch. The preferred thermal cracking conditions employ temperatures of about 900 to 1000 F., pressures of about 650 to 750 p. s. i., and a residence time of about 3 to 6 seconds. y The thermal cracking is ordisecure a conversion of about 24 to 31% for once-through and 15 to 20% for recycle operations of the heavy boiling feed to constituents boiling below the initial boiling point of the feed.

The total products of the thermal cracking operation are then passed to a distillation zone 31 operated at subatmospheric pressures of about 2 to 20 mm. Hg absolute. By introducing the thermally cracked products to this flash zone at a temperature of about 550 to 600 F., lighter thermally cracked constituents are flashed or vaporized and are removed overhead through line 32 of flash zone 31. This distillation operation should be conducted to permit removal as a bottoms product through line 33 of a heavy material having a softening point of 140 to 190 F., a specific gravity at 60 F., of 1.0 to 1.2, and a llash point above 450 F.v If desired, the total Table I. For comparative purposes, the properties 0f the base asphalt are also given in this table.

Table I Enamel Bituminous Base .percent.. 100 60 Slate Flour through 325 Mesh... .do 0 30 Mica F do.... 0 10 Specific Gravity at F 1. 132 l. 531 Flash (COC), "F 535 530 softening Point, (R. & B.), F 192 208 Penetration 77/100 g./5". 0 0 Penetration 100 g./5 0 0 Penetration /100 g./5 3 1 Penetration /l00 fin/5I 21 15 Soluble in CS2. Wt. Percent 99.9 60. 0 Soluble in Varsol. Wt. Percent-. 47. 2 Ash, Percent (ASTM D-482).--- 37. 4 Temperature for 2 Poses Vis., F 338 435 Temperature tor 18 Poises Vis., F 285 332 Sh7a7t7tFer Test-No. of grams for onc-blow failure at sup 'rsi'iiirIis'z' iirsi'iiicli o. 062 Chill Test, Failure at F 32 20 Setliing Test, 5 Hrs./400F. Rat Ash tm Ash r g 1. 31 p Hardness Index, 77"F.l 107 177 vnarily conducted in accordance with this invention to l Hardness Aindex dened as yield point determined by successive penetration-time relationship.

- second column shows the properties of a similar enamel which contains only slate flour as a filler. Column 3 shows the properties of a conventional enamel not made in accordance with this invention constituting 40% of 'slate flour admixed with a noncatalytically cracked ther- Imally cracked tar which has been tire and steam reduced to a 180 to 190 F. softening point. Finally, the last two columns of Table II show the properties of enamels prepared by mixing slate flour with cold tar.

The air-blowing maybe v Table II Air Blowing Air Blowing Mixing a Vacuum Rea Vacuum Re Slate Flour duced 160 F. duced 140 F. With Fire and .v softening Point, Soitening Point, Steam Reduced Catalytically Catolyticelly- IBO/100 F. 30% of Slate Flour v Cracked Ther- Cracked Thersoftening Point, Mixed With Coal Tar mally Cracked mally Cracked Non-Catalytic Tar With Slate Tar With 40% Cracked Ther- Flour and Mica Slate Flour mally'lracked Hardness Index 177 '44 56 160 81 -Shatter Resistance (Grams for 1 blow failure). 28 19 8 8 28 Temp. for 2 poise Vis., 435 399 455 373 463 Temp. for 18 Polse Vis., F.. 332 308 351 303 343 Slip, inches 160 F., 2 hrs. 4 56s 56 54 2 Settling .(Ash bottom/Ash Orig.) 1.31 1. 47 2. 43 1. 29 Chill, failure@ F 32 )20 32 20 32 20 32 20 32 20 Sottenmg Point (R. & B.) F-. 208 192 205 200 200 Specic Gravity F 1.531 1. 515 1. 484 1. 402 l. 618 Flash, CCC, F 530 590 555 465 495 Penetration 77/100 g.,5 0 0 0 0 0 Penetration /100 g./5I 0 4 0 2 Penetration /100 g./5-. 1 4 7 1 8 Penetration /100 g./5" 15 31 22 13 31 Ash, Wt. Percent (ASTM D-482) 37.4 38.4 40.2 26.3 27.9

As shown by the data of Table II, the preferred enamel asphalt derived from an asphalt material derived by catacomposition of this invention Vcharacterized in column l of the table is superior to all other enamels shown in the table. The superiority is established by considering the properties of hardness, shatter resistance, slip characteristics, settling characteristics, and the application temperature. The enamel of column 2, which is an enamel within the scope of this invention, exhibits good properties and is superior to the similar enamel of column 3, which, however, was not vacuum reduced. The superiority of vacuum reduction as compared to tire and steam reduction is shown by comparing the properties of shatter resistance, slip characteristics, ash point, and application temperature. This data therefore establishes the desirable properties of the enamels of this invention cornpared to conventional enamels. Furthermore, the data shows the particular benefit obtained in preparing the enamel of this invention by vacuum reducing the catalytically cracked-thermally cracked tar to the desired softening point.

What is claimed is:

lytic cracking of a heavy boiling fraction of a petroleum crude oil to provide a catalytic cycle oil, said cycle oil being thermally cracked and vacuum reduced to provide -heavy boiling fraction of a petroleum crude oil to pro- 'a tar, said tar thereafter being air-blown to provide an asphalt containing at least about 95% of aromatic hydrocarbons and'having a softening point of about 160 to 200 F., in combination with about 40% of a ller.

3. The enamel dened by claim 2 in which the said ller is a mixture of slate flour and mica.

4. A process for preparing an improved asphalt for enamel compositions comprising catalytically cracking a vide a catalytic cycle oil, thermally cracking said catalytic cycle oil and segregating a tar fraction, and vacuum reducing said tar fraction and oxidizing the tar to provide an asphalt containing at least about 95% of aromatic hydrocarbons and having a softening point of about to 210 F.

References Cited in the iilc of this patent l. An asphalt material derived by catalytic cracking .45 UNITED STATES PATENTS of a heavy boiling fraction of a petroleum crude 011 to provide a catalytic cycle oil, said cycle oil being ther. 2,096,876 Dltzer Oct. 26, 1937 mally cracked and vacuum reduced to provide a tar, said 2,220,714 Hersbergcr Nov. 5, 1940 tar thereafter being air-blown to provide an asphalt con- 2,305,440 Noel Dec. 15, 1942 taining at least about 95 of aromatic hydrocarbons and 50 2,383,701 Becker et al Allg. 28 1945 having a softening point of about 160 F. to 210 F. 2,384,671 Fratis Sept. 11, 1945 2. An asphalt enamel including about 60% of an 2,608,470 Helmers et al. Aug. 26, 1952 

1. AN ASPHALT MATERIAL DERIVED BY CATALYTIC CRACKING OF A HEAVY BOILING FRACTION OF A PETROLEUM CRUDE OIL TO PROVIDE A CATALYTIC CYCLE OIL, SAID CYCLE OIL BEING THERMALLY CRACKED AND VACUUM REDUCED TO PROVIDE A TAR, SAID TAR THEREAFTER BEING AIR-BLOWN TO PROVIDE AN ASPHALT CONTAINING AT LEAST ABOUT 95% OF AROMATIC HYDROCARBONS AND HAVING A SOFTENING POINT OF ABOUT 160*F. TO 210*F. 